Method of treating chlorates for



Reissued Dec. 11 1934 PATENT OFFICE METHOD OF TREATING oHLoRA'rEs ronBLASTING PURPOSES AND PRODUCT THEREOF Leonid Ivanoff, Helsingfors, andPer Olov Bjiirkman, Tainionkoski, Finland No Drawing. Original No.1,899,076, dated February 28, 1933, Serial No. 494,806, November 10,1930, and in Sweden May 8, 1928. Application for reissue May 12, 1934,Serial No. 725,396

' Claims.

This invention relates to an improved method of treating chlorates forblasting purposes and.

the briquette product of said method.

It is already known to use for blasting pur- ,,poses oxidizingsubstances, such as for instance 'chlorates, and to mix them immediatelybefore the use with combustible substances, such as for instancecombustible liquids. The manufacture of such explosives as well as theirtransport and use is quite as safe as the manufacture and use of purechlorate due to the fact that the two.

,.a perfectly good explosive and especially it was troublesome to bringtogether the ingredients of the explosive in the desired proportions.

The chief object of this invention is to bring the chlorate into a formwhich is well suited for use in the manufacture of explosives consistingof chlorate as oxidizing agent and a combustible agent.

,The invention consists, chiefly, in this that the chlorate with orwithout additions which do not make the mixture-explosive per se isbrought to a finely divided or dusty and moist state and then compressedand dried under heating, thus cementing the chlorate grains together tosolid porous briquettes the porosity of which amounts at least to 10% byvolume. The desired porosity is obtained by suitably selecting thepressure used, the fineness of the chlorate, its natural or artificialpercentage of moisture and the quantity of other additions possiblyused. The chlorate used may consist of potassium chlorate, sodiumchlorate or any other chlorate or perchlorate hitherto used for blastingpurposes.

Before the chlorate is moulded into briquettes it is disintegrated tosuch a fineness that at least of the powder passes through a sieve with80 to meshes pr. cm. Immediately before the use of the briquettes forblasting purposes they are impregnated with combustible substances inthe form of liquids, solutions or melts until they are partly or whollysaturated therewith.

The briquettes are, preferably, coated at the moulding or afterwardswith one or more envelopes adhering to the surface as a protecting coverduring transport and storing. The briquettes are, preferably, madetubular in such manner that they are provided with one or more channelsfor the purpose of facilitating the absorption of the combustiblesubstances and the introduction of a detonator.

The impregnation of the briquettes is, preferably, carried out, in suchmanner that the briquettes are charged into a vessel, vat or the like,containing the combustible liquid which then in a few minutes isabsorbed by the briquettes. The maximum quantity of liquid absorbed isdetermined beforehand by the porosity of the briquettes but it may beregulated at will by dipping the briquettes into the liquid only for amore or less shortperiod. In such manner also-the explosive power isregulated. Only after said impregnation which is effected in a fewminutes the briquette is a finished explosive which may be brought'toexplode only by a powerful detonator (No. 6 or No. 8). The briquettesare in other r'ee spects quite safe, 1. e. insensible to heat and tomechanical stress. If they for instance are held in a flame before theimpregnation they only melt as a stick of sealing'wax' and inimpregnated state they burn without exploding. The risk at the handlingof the explosive is thus practically limited to the moment of chargingor the moment of explosion.

As impregnating liquid any combustible liquid or solution may be used,as for instance petrolee um and other liquid hydrocarbons, benzol,nitrobenzol, creosote oil, syrup, solutions of resin in alcohol, etc.Also combustible solid or halfsolid substances may be used if they inmolten state can be absorbed by the briquettes. Substances of the latterkind are for instance paraflin and other solid or semi-solidhydrocarbons and they may be used especially for the manufacture ofexplosives for blasting in water or in watery borings. By a suitablechoice of liquid and the quantity thereof the explosive may be suited todifferent purposes and for obtaining the most suitable blasting effect.The explosive may thus be obtained either with properties like those ofblack gun-powder with its slow combustion or like that of dynamite withits rapid decomposition. The chlorate briquettes according to theinvention may, therefore, be regarded as a universal explosive.

In order to obtain briquettes of a good and uniform quality it issuitable to reduce the internal friction of the mass and thus increaseits plasticity. This may be done by adding substances such as an aqueousextract of peat, oils, gelatinous precipitates, tannin, graphite,kieselguhr, etc., to the mass before or during its moulding tobriquettes. By the addition of substances which at the drying of thebriquettes shrink, for instance by loss of gases or water, or aregasifled, for instance volatile substances such as amsition of thechlorate or increase the combustion;

Such catalytically and explosion temperature. acting substances are forinstance compounds of iron, copper, cobalt, nickel, chromium andmanganese, graphite, cyanides and sulphocyanides, etc., while carbides,certain metal powders such as powder of aluminium, magnesium, silicon.or

silicon metals, etc., may be used as energy delivering means. It is,however, to be noted that said additions should be used in suchquantities only that the dried and unimpregnated briquettes maintain thedesired porosity and do not become explosive per se. A suitable mannerof incorporating vsuch additional substances .in the briquettes istoadd. them to the powdered chlorate as suspensions, emulsions,colloidal or molec-' ular-dispersoidal solutions or to precipitate themin the chlorate powder during the mixing operation.

Another manner of introducing for instance the catalytically actingsubstances or substances having a high caloric value is to suspend suchsubstances colloidally or in other manner in the combustible liquids,solutions or melts with which the briquettes are to be impregnated.

The explosive power of the briquettes may be regulated not only by thenature and the quantity of impregnating liquid used but also by thechoice of detonating means and its quantity.

What we claim is: I 1. Method of treating chlorates for blastingpurposes, which comprises mixing finely disintegrated chlorate and waterto form a plastic mass, moulding said mass into blocks, drying saidblocks until the chlorate dissolved crystallizes out and cementstogether the chlorate powder to porous briquettes having capillarity andadapted to be impregnated with a combustible liquid, the quantity ofwater used being so reof the total volume of the briquette.

2; Method of treating chlorates for blasting purposes, which comprisesmixing finely disintegrated chlorate and water to form a plastic mass,moulding said mass into blocks while applying pressure to compress themass, drying said blocks until the chlorate dissolved crystallizes outand cements together the chlorate powder to porous briquettes havingcapillarity and adapted to be impregnated with a combustible liquid,-thequantity of water and the pressure used being so chosen that the porevolume of the finished porous briquette amounts to at least 10% of thetotal volume of the briquette.

3. Method of treating chlorates for blasting purposes, which comprisesmixing finely disintegrated chlorate, water and a substance whichshrinks by drying, to form a plastic mass, moulding said mass intoblocks, drying said blocks until the chlorate dissolved crystallizes outand cements together the chlorate powder to porous briquettes adapted tobe impregnated with a combustible liquid, the quantity of water being sorelated to the other ingredients of the plastic mass that the porevolume of the finished porous briquette amounts to at least 10% of thetotal volume of the briquette.

4. Method of treating chlorates for blasting purposes, which comprisesmixing finely disintegrated chlorate, water and a solid volatilesubstance to form a plastic mass, moulding said mass into blocks,heating said blocks to expel the water and the volatile substance and tocement together the chlorate powder to porous briquettes adapted to beimpregnated with a combustible liquid, the quantities of Water and ofthe volatile substance being so related to the chlorate that the porevolume of the finished porous briquette amounts to at least 10% of thetotal volume of the briquette.

5. As a new article of manufacture a chlorate briquette for blastingpurposes composed of powdered particles of chlorate cemented together byfine crystalline particles of chlorate forming a solid coherent body ofdesired porosity such that the pore volume is predeterminedand amountsto at least 10% of the total volume of the briquette.

LEONID IVANOFF.

PER OLOV BJGRKMAN.

